Concordance of glycaemic and cardiometabolic traits between Indian women with history of gestational diabetes mellitus and their spouses: an opportunity to target the household Abstract Aims/hypothesis The aim of this study was to investigate the concordance of dysglycaemia (prediabetes or diabetes) and cardiometabolic traits between women with a history of gestational diabetes mellitus (GDM) and their spouses. Methods Using hospital medical records, women with GDM (diagnosed between 2012 and 2016) and their spouses were invited to participate in the study and to attend a scheduled hospital visit in a fasting state. Sociodemographic, anthropometric and medical data were collected, and a 75 g OGTT with serum insulin estimation, HbA1c measurement and fasting lipid profile were performed at the visit. Prediabetes and diabetes were defined using ADA criteria and the metabolic syndrome was defined using IDF criteria. Results A total of 214 couples participated in the study. Women were tested at a mean ± SD age of 32.4 ± 4.6 years and median (quartile [q]25–q75) of 19.5 (11–44) months following the index delivery, while men were tested at a mean ± SD age of 36.4 ± 5.4 years. A total of 72 (33.6%) couples showed concordance for dysglycaemia, while 99 (46.3%) and 51 (23.8%) couples were concordant for overweight/obesity and the metabolic syndrome, respectively. A total of 146 (68.2%) couples showed concordance for any of the above three factors. The presence of dysglycaemia in one partner was associated with an increased risk of dysglycaemia in the other partner (OR 1.80 [95% CI 1.04, 3.11]). Similarly, being overweight/obese (OR 2.19 [95% CI 1.22, 3.93]) and presence of the metabolic syndrome (OR 2.01 [95% CI 1.16, 3.50]) in one partner was associated with an increased risk of these conditions in the other partner. Both women and men were more likely to have dysglycaemia if they had a partner with dysglycaemia. Women with a partner with dysglycaemia had a significantly higher BMI, waist circumference and diastolic BP, and a significantly higher probability of low HDL-cholesterol (<1.29 mmol/l) and the metabolic syndrome compared with women with a normoglycaemic partner. No such differences were observed for men with or without a partner with dysglycaemia. Conclusions/interpretation The high degree of spousal concordance found in this study suggests social clustering of glycaemic and cardiometabolic traits among biologically unrelated individuals. This provides us with an opportunity to target the behavioural interventions at the level of the ‘married couple’, which may be a novel and cost-effective method of combating the current diabetes epidemic.